Tay-Sachs disease is an inherited condition characterized by progressive destruction of nerve cells in the brain and spinal cord. This condition, caused by a defect in the HEXA gene, is passed from parent to child. Symptoms include blindness, dementia, and the inability to swallow. Tay-Sachs disease is rare among the general population, but occurs in approximately 1 in every 27 people of the Ashkenazi Jewish heritage.
What Is Tay-Sachs Disease?
Tay-Sachs disease is a rare, inherited disorder that causes progressive destruction of nerve cells located in the brain and spinal cord.
How Common Is It?
Tay-Sachs disease is rare in the general population. The genetic mutations that cause the disease are more common in people of Ashkenazi (eastern and central European) Jewish heritage than in those of other backgrounds. Approximately 1 in every 27 Jews in the United States is a carrier of the gene.
The genetic mutations that cause Tay-Sachs disease are also more common in:
- Certain French-Canadian communities of Quebec
- Some Amish groups
- The Cajun community of Louisiana.
Causes of Tay-Sachs Disease
Tay-Sachs disease is a condition that is passed from parent to child through a defect (mutation) of the HEXA gene located on chromosome number 15. The HEXA gene is responsible for making a vital enzyme called hexosaminidase-A (HEXA). Without HEXA, a fatty substance (lipid) called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain.
(Click Causes of Tay-Sachs to learn more.)
Is the Disease Inherited?
Tay-Sachs disease is an autosomal recessive condition, which means that both parents must have this defective gene in order for a child to inherit it.
When both parents are carriers (meaning that one HEXA gene is normal and one is defective but they have no symptoms), each child has a 25 percent chance of having the disease and a 50 percent chance of being a carrier.
(Click Inheriting Tay-Sachs for more information.)